1. Field of the Invention
The present invention generally relates to the field of display systems, and particularly to a head worn head up display (HUD) for providing an enhanced head down environment.
2. Description of the Related Art
Effective flight management of aircraft is closely related to providing accurate and timely information to the pilot. This should be done in a manner that succinctly but accurately conveys to the pilot information important to the safe operation of the aircraft.
A principal flight instrumentation display is a dynamic head down display, also known as the Primary Flight Display (PFD), which shows information about course, speed, altitude, rate of climb and other information. The PFD is usually an electronic display such as a cathode ray tube or back-lit liquid crystal display.
Because of the already crowded and busy nature of the PFD screen, it is difficult to add new information in a manner that can be easily and quickly grasped by the pilot. In general, the new information almost always has to be placed in an already defined field on the display. However, it cannot replace unrelated essential information. For example, more detailed navigation information cannot be placed in the display area reserved for a different category of information such as speed, altitude, heading, etc.
A Head Up Display (HUD) is a means of projecting information directly into a human's visual field. The HUD was pioneered for military aviation and has since been used in other applications. HUDs are typically used in aircraft to provide pilots with information superimposed onto their forward field of view through the aircraft windshield. The information displayed may be data or symbolic images indicative of flight conditions such as the operating condition of the aircraft, environmental information or guidance information for use in directing the aircraft to its destination. These images are presented in overlying fashion on the pilot's field of view so as not to interfere with the pilot's view of the background scene.
As noted above, within a constrained cockpit environment, there is a very high density of controls to interact with and monitor. Traditional HUDs with combiners hung from the ceiling or mounted atop the glareshield can only be used when the user's eye is within the design eye box which is typically quite small (4″×2″×4″ is typical). It can be very difficult for the user to simultaneously use the traditional HUD and also continue to utilize the remainder of the head down instrumentation.
Head Worn Head Up Displays have been in use in many environments, including military flight environments, for many years. Such head worn displays are also referred to as Head Mounted displays. The symbology used on these displays has included flight guidance information, weapon aiming and status information, and even some aircraft status information. A key aspect of previous usage is that most of the symbology was designed for use with the pilot looking outside of the cockpit. Present assignee, Rockwell Collins, Inc. manufactures several models of head worn head up displays. These models include the ProView SO35, ProView XL50, PV40/50STm, SIM EYE XL100A, ProView V035, and ProView SO35-A.
As will be disclosed below, the present invention provides a synergistic result by utilization of the head down display in combination with the head up display.